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Detailed Sampling for Process
Modeling of Nitrogen and
Phosphorus Removal
OWEA 2013 Annual Conference
June 19, 2013
Will Martin
Alyssa Mayer
SWOWEA YP Award
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• Biological Process Models Overview
• Process Sampling Overview
• Sampling Plans – Overview and Preliminary Steps
• Sampling Plans – Development
• Case Study #1: Upper Mill Creek WRF
• On-site Coordination
• Case Study #2: Sycamore Creek WWTP
• Summary
Presentation Overview
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Process Model Whole plant models
Anaerobic Zone
Influent Anoxic Zone Aerobic
Zone
Secondary
Clarifier
Temperature Model
Gas Transfer Model
Activated Sludge Model -Process Stoichiometry
-Process Kinetics
Reactor Model
Hydrodynamic Mixing Model (eg CSTR, Plug
Flow, etc)
Influent Wastewater Characterization Model
Sedimentation/ Clarification Model
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Process Model Uses and Benefits
• Planning / Design Capacity Analysis
Alternative Evaluation
Design Optimization
• Process Optimization Nutrient Removal
Wet Weather
Aeration
• Training
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Benefit of Process Sampling
• Junk in = Junk out - ANY inputs can be simulated
• OBJECTIVE – calibrate model so results are representative of observed plant performance
Highlight process issues
Confidence for scenarios outside historical data
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Benefit of Process Sampling
Example Process Issue
• WWTP with floating sludge issues
• Detailed process model sampling
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Model Inputs and Variables What Usually Changes?
From WERF 2003 “Methods for Wastewater Characterization in Activated Sludge Modeling”
Highly
Variable and
Plant Specific
Plant Specific
Default Values
Recommended
Typically
Constant
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Influent Characteristic Sampling Why?
• NPDES Sampling
cBOD5
TKN
TSS
TP
• COD Driven
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Influent Characteristic Sampling Why?
• Sensitive to Nutrient fractions
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Influent Characteristic Sampling Site Specific
From WERF 2003 “Methods for Wastewater Characterization in Activated Sludge Modeling”
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Influent Characteristics BNR Plants
• Special Emphasis for BNR Plants – Denitrification
Denitrification is driven by carbon consumption • Influent COD fractions
Denitrification must have anoxic conditions – DO Profiling
• Special Emphasis for BNR Plants – BioP
Phosphorous Release driven by rbCOD (VFAs) • Influent or sidestream COD fractions
• Special Emphasis for BNR Plants – Both
Sidestream sampling – up to 20% of Nitrogen and 30% of Phosphorous loads
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Sampling Plans Overview
• Guidelines apply to WWTPs of all sizes and configurations - tailor accordingly
• Sampling plans vary in size from 100 to 2,500 analyses
• H&S Cincinnati Office Sampling Experience
1.5 MGD to 55 MGD WWTPs
Traditional Activated Sludge, Bio-P Process (VIP and A2O), Counter Current Aeration
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Sampling and Sampling Plans Good vs. Bad
• Well executed sampling is like a surgeon’s scalpel:
Minimally invasive
Highly informative
“According” to plan – first try on most things
• Poorly executed sampling is like a machete:
Highly disruptive to WWTP operators and lab staff
Lots of unnecessary data is collected or critical data is missed
Significant rework
LONG days
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Sampling Plans – Preliminary Steps Compile Plant Historical Data
• Physical Plant Data
Tank dimensions and configurations
Blower and pump sizes
• Water Quality Data
Influent & Effluent – MOR
Nutrient profiles, sludge disposal data
• Operational Data
Flow measurements
SRT, DO set-points
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Sampling Plans – Preliminary Steps Review Trends and Data Quality
• Develop Trends
• Perform Mass Balances
• Calculate Yields
• Preliminary Modeling
• Identify Gaps and
Data Quality Issues
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Sampling Plans – Preliminary Steps Site Visits and Meetings with Operators
• Determine:
Flow paths
Recycle streams
Chemical usage
Wet weather operation
Dewatering operations
Aeration strategy
Temporary on-site lab location
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Sampling Plan Development Duration and Timing
• Representative Dry Weather Period
• Capture Typical Variation
Throughout the day
Throughout the week
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Sampling Plan Development Sample Types
COMPOSITES
DIURNAL GRABS
PROCESS GRABS
SIDESTREAM GRABS
•Flow-Weighted, 24 hour Average
•Collected by an automatic composite sampler
•Collected each day of sampling period
•Comparison to plant-collected samples
•Collected using automatic samplers at discrete time periods
•Collected once every 1-2 hours, over 24 consecutive hours
on at least 2 separate days (one weekday and one weekend day)
•Collected manually at several time periods throughout the day
•Composited together to obtain a daily average
•Collected each day of sampling period
•Collected using “dippers” at discrete time periods
•Collected during peak and low loading periods
on at least 2 different days ( one weekday and weekend day)
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Sampling Plan Development Where and What?
• Select Locations
Influent
Recycles
Solids Train
Unit Process Input/Outputs
BNR Tank Profiles
Parameters
TSS/VSS NO2-N
COD Total P
BOD5 PO4-P
cBOD5 Ca
TKN Mg
NH3-N Alkalinity
NO3-N pH
• Choose Parameters for Analysis
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Sampling Plan Development Parameter Guidelines
Typical Plant Critical Sampling Locations and Parameters (Partial List)
Plant Area Solids COD VFAs Nitrogen Phosphorous Other
Influent TSS,VSS
XX, XG, XF,
XM
Bio-P
Only TKN, NH3 TP, PO4
Alk, pH,
Mg, Ca
Primary Effluent TSS,VSS
XX, XG, XF,
XM
Bio-P
Only TKN, NH3 TP, PO4
Primary Sludge TSS,VSS
Aeration Basins -
MLSS TSS,VSS NH3, NO2, NO3 TP, PO4
RAS TSS,VSS NH3 TP, PO4
Secondary Effluent TSS,VSS
XX, XG, XF,
XM
TKN, NH3, NO2,
NO3 TP, PO4
Return Streams TSS,VSS XX, XG
Bio-P
Only
TKN, NH3, NO2,
NO3 TP, PO4 Alk, pH
Abbreviations: TSS = Total Suspended Solids, VSS = Volatile Suspended Solids, XX = Total Fraction, XG = 1.2 um
filter Fraction, XF = Floc Filter Fraction, XM = 0.45 um filter Fraction, TKN = Total Kjehldahl Nitrogen, NH3 =
Ammonia-N, NO3 = Nitrate-N, NO2 = Nitrite-N, TP = Total Phosphorous, PO4 = Ortho Phosphate, Alk =
Alkalinity, Mg = Magnesium, Ca = Calcium
Note: Refer to Table 21-1 in WERF Sampling Guidelines for Full Detailed List
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Sampling Plan Development Case Study #1: Upper Mill Creek WRF
Plant Sampler
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Sampling Plan Development Case Study #1: Upper Mill Creek WRF
Influent Pump Station
West Influent East Influent
Filter
Backwash Centrate
Combined
Influent
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Sampling Plan Development Case Study #1: Upper Mill Creek WRF
• Calculating “True” Influent
By Addition
By Subtraction
• Developed correction factors to use historical data
West East +
Centrate & Filter BW
Combined
Influent -
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Sampling Plan Summary
~1,700 analyses
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• What?
On-site Coordination Cost Effective Distribution of Labor
• Who?
Consultant
Plant Operators
Plant Lab Staff
Contract Lab Operational
Data
Sample Collection
Sample Prep
Analysis
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On-site Coordination Guidelines for Sample Collection
• Well-mixed, representative locations
• Test everything before event
• Time constraints • pH measurement right away
• Immediate MLSS removal from any sample measured for soluble parameters
Sample Collection
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On-site Coordination Flow meters, probes etc.
Operational Data
• Coordinate operational data collection
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On-site Coordination Typical Sample Breakdown
Sample Prep
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• Contract Lab or Plant Lab
Bottle order (size, preservatives)
Chain of Custody Development
Coordinate picks-ups to meet hold time requirements
On-site Coordination Splitting Samples for Analysis
Sample Prep
• Temporary Lab On-Site (Consultant)
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On-site Coordination On-site Capabilities
Analysis
• Hach TNT+ kits
• COD
• TKN, TN, NH3, NO3
• TP, PO4
• pH
• Duplicates run by multiple labs
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On-site Coordination Case Study #2: Sycamore Creek WWTP
~350 Samples Collected and
~2,000 Total Analyses
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On-site Coordination Case Study #2: Sycamore Creek WWTP
• N and P Removal at Sycamore
1 anaerobic zone
2 anoxic zones
2 aerated passes
Anoxic 2 Anoxic 1
A
B
C EFF
Anaerobic
INF
ARCY
RAS
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On-site Coordination Case Study #2: Sycamore Creek WWTP
• Nutrient profile results
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Keys to a Successful Sampling Event
• Detailed understanding of plant layout and operations
• Planning, Planning, Planning
• Realistic assessment of capabilities (equipment, man power, budget)
• Good communication with all parties
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Acknowledgements
• Upper Mill Creek WRF, Butler County Water and Sewer:
• Todd Madden (Plant Supervisor), Jeremy Hamel and the rest of the UMC operations staff.
• Sycamore Creek WWTP, Metropolitan Sewer District of Greater Cincinnati:
• Dave Wilson (Plant Supervisor), Barb Browne (Area Supervisor), Joe Baer, Jason Grooms and the rest of the SCWWTP operations staff.
